The present invention relates to reclosable plastic bags and in particular to a method and for forming, filling and sealing such bags.
In U.S. Pat. No. 4,709,533 there is disclosed a method and apparatus for forming, filling and sealing reclosable plastic wherein the edges of a film of bag material are brought together into a fin at a form, fill and seal (FFS) machine and a zipper is fed into and sealed to the fin. While the disclosed method of this patent works fine for the manufacture of relatively simple reclosable packages, problems are countered in the production of more sophisticated packages such as where a slider is to be attached to the zipper or where a hermetic seal is required or desired to protect the package contents.
In view of the above, it is the principal object of the present invention to provide an improved method for the manufacture of reclosable packages on a form fill and seal machine which enables the placement of sliders on the zipper during the package manufacturing process. A further object is to provide such a method that also permits the formation of a peel seal below the zipper during the package formation process.
Still another object is to provide such a method that can be practiced on conventional FFS equipment with modifications that may readily be made.
Still a further object is to provide the equipment for practicing the desired method. The above and other beneficial objects and advantages are attained in accordance with the present invention by advancing a film of package making material longitudinally to form a tube while guiding opposite longitudinal edges of the film into a fin. A zipper having interlocking members and an attached flange is fed into the fin by capturing external surfaces of the interlocking members within a first guide member positioned adjacent to said fin and feeding the flanges along opposite sides of a second guide member positioned within said fin. The flanges are attached to respective sides of the fin by sealing against the second guide. One of the flanges extends beyond the other flange. The flange extension is attached to the side of the fin adjacent to the other flange with a peel seal. The interlocking members are stomped together at bag length intervals and a slider is attached to the interlocking members between each pair of adjacent stomps.